独塔斜拉桥的抗震分析及减隔震措施研究

对于大跨径斜拉桥，抗震计算涉及的因素较多，需要根据其自身特点，进行专项研究，以昆阳路闵浦三桥为研究对象，分别采用反应谱法和时程分析法对半飘浮体系独塔斜拉桥的结构地震响应进行对比分析，选取合适的地震波和阻尼参数。在E2地震作用下，采用时程分析法分别对塔梁间纵向约束支座剪坏前后两种不同的受力体系进行分析，结果表明，对支座剪坏前的纵向约束体系，主塔支座承受较大的水平力，而对支座剪坏后的纵向活动体系，主塔塔顶位移和主梁梁端的纵向位移均较大。针对大跨度独塔斜拉桥桥型方案特点，采用减隔震组合体系，不仅可大幅降低塔底纵向受力，同时可将塔顶和梁端的纵向位移控制在合理范围之内，是理想的抗震约束体系。

Analysis and Study on Seismic Resistance and Isolation Measures of Single-pylon Cable-stayed Bridge

For the long-span cable-stayed bridges, there are many influential factors on the seismic calculation. It is required to base on its own characteristics for the special study. Taking Minpu Bridge III in Kunyang Road as the study object, the response spectrum method and time-procedure analysis method are used to compare and analyze the structural seismic response of semi-floating single-pylon cable-stayed bridge. The suitable seismic wave and damping parameters are selected. Under the E2 earthquake, the time-procedure analysis method is used to analyze two different stress systems before and after the bad shear of the vertical restraint support between the pylon and beam. The result shows that the main pylon supports bear the large horizontal force for the vertical restraint system before the bad shear of support. The displacement at the top of the main pylon and the longitudinal displacement at the end of the main girder are all large for the vertical activity system after the bad shear of the supports. Aiming at the scheme characteristics of long-span single-pylon cable-stayed bridge, the composite system of seismic mitigation and absorption is used to greatly reduce the longitudinal stress of pylon bottom and also to control the vertical displacements of the pylon top and beam end within the reasonable range, which is the ideal seismic isolation restraint system.